Handbook of the Nautical Rules of the Road by Llana & Wisneskey

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Rule 19 -- Conduct of Vessels in Restricted Visibility


Section/Subpart III (Conduct of Vessels in Restricted Visibility) contains but one Rule--Rule 19. Section I specified Conduct of Vessels in Any Condition of Visibility, and Section II specified Conduct of Vessels in Sight of One Another. The title of Section III is the same as that of Rule 19. International Rule 19 is identical to Inland Rule 19 except for a few minor style changes that do not affect substance.


INTERNATIONAL

INLAND

(a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility.

(a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility.

 

How poor must visibility be in order to be called "restricted?" The Rule 3 definition does not explain that but does give examples of natural phenomena that can impair visibility: fog, mist, falling snow, heavy rainstorms, sandstorms, and so on. Obviously, if visibility is restricted by haze to ten miles, you would not be in an area of restricted visibility. What would be called restricted visibility naturally depends on the circumstances. In open water if you cannot see five miles in all directions you are operating in or near restricted visibility. In more confined bodies of water the distance may be less.

Why is it that only one Steering and Sailing Rule is devoted exclusively to conditions of restricted visibility while there are eight Rules for much better conditions? The reason is that when a situation can be better perceived it merits more detailed and specific recommendations and requirements. There are simply more options available.

In restricted visibility, on the other hand, you can't see if there are vessels around you, where they are, how big they are, what kind they are, or what their courses and speeds are. Radar helps, but not enough.

Without the benefit of good visibility, Rules 4 through 10, which apply to the conduct of vessels in any condition of visibility, become that much more important. Indeed, much of Rule 19 repeats and emphasizes the contents of Rules 4-10, and it essentially says to be extra careful.

It is important to remember that the navigation rules contain two rather distinct sets of rules: one for when you can see the other vessel, and one when you can't. The Rules for vessels in sight of one another (11 through 18) naturally predominate and may become so second nature that they may be difficult to put aside in conditions of restricted visibility. When the visibility is so poor that you cannot see the vessels around you, you must forget about Rules 11 through 18. There will be no "stand-on vessel." There will be no holding course and speed. The overtaken as well as the overtaking vessel are equally obligated to act to avoid collision. Restricted visibility is the great equalizer.

Paragraph (a) cites two conditions that make Rule 19 applicable. Both conditions must be present. The first is that the vessels must not be in sight of one another. If they are, then Rules 11 through 18 apply instead of 19. Remember that "in sight" means "observed visually."

The second is that the vessel must be in or near an area of restricted visibility. Your vessel may be in an area of good visibility but may also be close to a fogbank or thundershower that could be concealing one or more vessels. Even though you are in the clear, you must follow Rule 19 (and sound the signal required by Rule 35).

However, with respect to another vessel in your area of good visibility or a vessel that emerges (early enough) from the fogbank, you must follow Rules 11 through 18 (and sound any signals required by Rule 34). It is therefore possible for you to be following at the same time rules for good visibility and the rules for restricted visibility.


INTERNATIONAL

INLAND

(b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and conditions of restricted visibility. A power-driven vessel shall have her engines ready for immediate maneuver.

(b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and conditions of restricted visibility. A power-driven vessel shall have her engines ready for immediate maneuver.

 

Paragraph (b) repeats the mandate of Rule 6 to proceed at a safe speed, making explicit the requirement to have engines ready for immediate maneuvering when in or near areas of restricted visibility. This applies to open waters as well as more confined waters.

Safe speed does not necessarily mean slow speed. Sometimes it is better to proceed fast enough for effective rudder action.


INTERNATIONAL

INLAND

(c) Every vessel shall have due regard to the prevailing circumstnces and conditions of restricted visibility when complying with the Rules of Section I of this part.

(c) Every vessel shall have due regard to the prevailing circumstnces and conditions of restricted visibility when complying with the Rules 4 through 10.

 

Paragraph (c) adds no new requirement but does push mariners into closer scrutiny of Rules 4 through 10. Rules 5, 6, and 7 are particularly important for vessels navigating in restricted visibility.


INTERNATIONAL

INLAND

(d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration of course, so far as possible the following shall be avoided:

(i) an alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken;

(ii) an alteration of course towards a vessel abeam or abaft the beam.

(d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration of course, so far as possible the following shall be avoided:

(i) an alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken; and

(ii) an alteration of course towards a vessel abeam or abaft the beam.

 

Paragraph (d) summarizes the more detailed provisions in Rules 7 and 8 and adds specific guidance on evasive maneuvering. The recommended course changes are intended to prevent ships from turning into each other. Not surprisingly, this provision works only if both vessels follow it. What is surprising is the number of collisions that result because one operator thought turning the other way would work better. In any case, nothing in this paragraph suggests that course changes could be made in lieu of a speed reduction in areas of restricted visibility.


INTERNATIONAL

INLAND

(e) Except where it has been determined that a risk of collision does not exist, every vessel which hears apparently forward of her beam the fog signal of another vessel, or which cannot avoid a close-quarters situation with another vessel forward of her beam, shall reduce her speed to the minimum at which she can be kept on her course. She shall if necessary take all her way off and in any event navigate with extreme caution until danger of collision is over.

(e) Except where it has been determined that a risk of collision does not exist, every vessel which hears apparently forward of her beam the fog signal of another vessel, or which cannot avoid a close-quarters situation with another vessel forward of her beam, shall reduce her speed to the minimum at which she can be kept on her course. She shall if necessary take all her way off and in any event navigate with extreme caution until danger of collision is over.

 

Paragraph (e) directs every vessel to slow down or stop when it hears the fog signal of another vessel forward of the beam or knows another vessel lies ahead. This requirement no longer applies once the vessel knows for sure that risk of collision does not exist and will not develop. Paragraph (e) adds to Rule 6 (Safe Speed) and relies on the proper execution of Rule 7 (Risk of Collision). This provision applies to every vessel, not just the other vessel.

After detecting another vessel forward of the beam, a vessel must reduce its speed to the point of bare steerageway. Stopping engines will slow the vessel and may make it easier to hear the other vessel's signals. Do not change course until you know the other vessel's position, course, and speed. The other vessel's signals should indicate whether it is making way, stopped, or anchored, but do not rely on signals alone. Use all other means available for collecting information, including radar and radiotelephone. If you cannot quickly clarify the situation, do not continue blindly into the great unknown. Stop your vessel until you establish the location and intentions of the vessel(s) ahead.

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